Process for preparing petroleum sulfonates



Patented Dec 17, 1946 PROCESS FOR PREPARING PETROLEUM SULFONATES Jere C. Showalter, Goose Creek, Tex., assignorto Standard Oil Development Company, a corporation of Delaware Application August 21, 1944, Serial s 550.395

"dues or foreign bodies on the object being cleansed, and are particularly suitable for use as a. shampoo.

It is well known to produce sulfonic acids and salts of sulfonic acids of varying properties by treating mineral or petroleum oils with sulfuric acid of sulionating strength and subsequently neutralizing the sulfonic acids with an alkali to obtaln sulionates suitable for us as detergents and cleansing agents.

In accordance with the present invention, I propose to prepare water soluble salts of sulionates having novel characteristics by selecting the petroleum fraction to be sulfonated, by controlling the conditions of sulfonation and by employing a particular sequence oi steps in cleansing the sulfonic acids. By the careful control of 'the'steps of the process. I am able to obtain a metal salt of sulfonic acid readily soluble in water and appearing as a clear, light colored, aqueous solution. free from contaminating solid bodies and capable of being used as a detergent without leavlngan undesirable residue on the object being cleansed.

The present invention will now be described in conJunction with the drawing, in which the sole figure is in the form oi a flow sheet diagrammatically illustrating the process of the present invention.

A distillate fraction having a viscosity in the range of 75 to 85 seconds Saybolt at 100 F. and obtained by fractionation of a naphthenic crude oil is passed via inlet Ii into a solvent extraction unit l2, where it is contacted with phenol as the selective solvent under conditions to form 8. reffinate fraction and an extract fraction. The step of solvent extraction with selective solvents is well known to the art. and for this reason the operating conditions in this unit will not be described in detail. It will be suiiicient to say that usually the extract will have approximately 35% of the volume of the original distillate and the raifinate will comprise the remaining 65% of the distillate. The raflinate may be discarded from the solvent extraction unit via outlet l3 and the extract may be withdrawn through line 14 to acid treating unit I5. It will be understood that the unit designated by numeral [2 as the solvent extraction unit will include suitable distillation columns for 3Clahns. (on. was

recoveryoi the solvent employed and that the extract indicated asebeing removed from the unit vi'aiine ll 'willbe substantially free mm selective solvent. V

In acld treating unit IS the extract is admixed with "98%- sulfuric acid in amountsranging irom 300 to 400 pounds of acid per barrel of extract. In the acid treating step approximately of the extract is converted to sulfonated oil. The suli'onatlng' step lspreferably carried out with the extract and sulfuric acid initially at atmospheric temperatures, and Lie maximum temperature of the reactants increasing to a temperature in the range of to F. as the sulfonation reaction proceedsv From unit l5 the mixture of reactants is withdrawn by line I] to settler i8, where the reactants separate into a lower sludge layer, which is removed via line l9, and an upper layer or su1- fonated oil, which is removed through line 20. To the sulfonated oil flowing through line 20 is added water via inlet 21 in an amount rangin from 3% to 5% ,0: thesulfonated oll and the two comppne nts are;the n passed through mixing deyice 9 to cause the thorough admixture oi ,water with the 'sulionated oil and the mixture is then passed through line ill to a second settling vessel 22. The addition of the water to the mixturecausesa separation to take place in settler 22 witl'isulfi'onidacids andwater, in addition to entrained oil, settling as a bottom layer and unconverted oil separating as a top layer; The unconverted oil is withdrawn from the upper portion oi settler 22 via line 23 and discarded from the system'. The suifonic acids, water and oil entrained therein settling in the lower portion of vessel 22 are withdrawn via line 24.

To the mixture flowing in line 24 is added an alkali metal hydroxide via inlet 25 in an amount suiflcleht to neutralize the sulionlc acids. It is preferred to employ either sodium or potassium hydroxide and to add an amount Just suflicient to neutralize the suli'onic acids and convert them to sulionic soaps It will usually be found desirable to pass the mixture of sulionic acids and alkali metal hydroxide through mixer 26 in order to insure a thorough admixture of the components. While a series ofbafiies have been indicated in the schematic mixer shown in the drawing, it will be understood that a "essel provided with a mechanical stirrer may be employed and the mixture maintained in the vessel until the sulfonic acids have been neutralized with the hydroxide.

The solution of sulionic soaps is withdrawn the alcohol solution to one volume of the sulionic' soap solution. The constituents in line 21, are then passed into mixer 29, where they are thQr oughly admixed. The mixture is removed by line 30, where light hydrocarbon material is added by inlet II and then passed through a mixer 32' and line I3 into settling vessel 34. A number of light hydrocarbon fractions are suitable in the use of this extraction step. For example, liquefied propane, butane or pentane fractions may be used as well as higher boiling fractions, such as hexane or light naphtha or liquid mixtures including these constituents. It will usually be desirable to employ a light naphtha as the light hydrocarbon and to employ one volume of the light hydrocarbon to two volumes of the alcohol-sulionic soap solution. The addition of the isopropyl alcohol and light hydrocarbon to the aqueous sulfonic soap solution causes the segregation of the oil and light hydrocarbon as one fraction and the alcohol and aqueous soap solution as another fraction, and these two fractions are separated by settling in unit M. The oil and light hydrocarbon separates as an upper layer and is removed from unit 34 via outlet 35, and may be discarded. The lower layer, comprising alcohol and sulionic soap solution, is withdrawn through outlet 36 to a distillation column 31, where the alcohol is vaporized and removed as overhead via outlet ll.

The alcohol-tree sulionlc soap solution is withdrawn from the lower portion of the distillation tower 31 through line 38 and sent to a settling vessel 40, where it is allowed to settle for a substantial interval of time to separate a minor water-lnsoiuble soap fraction from the remaining portion oi the solution. It will be iound desirable to allow the solution to remain in settler 40 in a quiescent state for an interval of time of the order of 24 hours, After the mixture in unit 40 has settled to form an insoluble soap traction and a soluble soap fraction, the soluble soaps may be withdrawn as indicated through outlet Ii and the insoluble soaps may be withdrawn from the bottom of the vessel through outlet 42. Under some conditions the settling step in unit 40 may not remove all of the solids from the soluble soaps, and under such conditions it may be desirable to pass the water-soluble soaps via line I through filter 43 in order to obtain a purified water-soluble sulfonate solution, However. the settling step may separate substantially all of the solid materials from the water-soluble soaps, and if such be the case the filter may be bypassed by line H. Valve I3 is indicated for controlling the flow through filter '3 and valve 44' for controlling the flow through bypass line H. The purified aqueou solution of alkali metal salts of sulfonates may be passed either through filter 43 or bypass line 44 into outlet line 45. from which they may be withdrawn to suitable storage facilities, not shown.

The aqueous solution is line 5 is free from harsh alkalies and solid materials and is suitable for use as a detergent. The aqueous solution has been found suitable for use as a shampoo, and for such use it is desirable to employ a mixture comprising 15% of the alkali metal sulionates and 85% water. The water content of the solution may, of course, be readily controlled, but for purposes of illustration the addition of water thereto for controlling the concentration of the solution is indicated by inlet line IS.

The aqueous solution oi water-soluble alkali metal suifonates has a pH 01' 'l and is free from contaminating materials and solids which would be undesirable in a detergent material. The alkall metal salts oi thesuiionates are readily soluble in water, audit is, therefore, unecessary to employ a vehicle or solvent, such as alcohol, in the solution in order to maintain the sulionate salt in solution.

It is to be emphasized that the washing steps and settling steps in the described process are necessary in order to obtain a detergen-t'material having the characteristics given above. The omission of any of these steps results in a product which is not free from solids and gummy constituents and is unsuitable for use as a detergent in shampoos and like compositions. As stated above, the dual filtering step illustrated is optional and may be omitted in case satisfactory settling is obtained in the preceding vessel.

Having fully described the present invention, what I desire to claim is:

l. A method for producing a detergent suitable for use as a shampoo comprising the steps of extracting a naphthenlc distillate having a viscosity in the range of to seconds Saylbolt at F. with a selective solvent under conditions to form a raillnate and an extract, contacting the extract with concentrated sulfuric acid in the range oi 300 to 400 pounds of acid per barreel 01 extract under conditions to lorm a sludge layer and a sulionated oil layer, separating the sludge layer, adding from 3% to 5% ct water to the sulionated oil layer and settling .to produce an oil layer and a sulionlc acid layer, withdrawing the sulionic acid layer and contacting it with a solution of an alkali metal hydroxide to form a soap, mixing the soap with isopropyl alcohol, extracting the mixture with a light hydrocarbon, distilling the extracted soap to remove alcohol and light hydrocarbon therefrom and settling to form a layer of water-insoluble soap and a layer of water-soluble soap and removing the watersoluble soap as product.

2. A method for producing a detergent suitable for use as a shampoo comprising the steps of extracting a. naphthenic distillate having a viscosity in the range of '75 to 85 seconds Saybolt at 100 F. with a selective solvent maintained under conditions to form a rafllnate and an extract, separating the extract from the rafilnate and contacting it with 98% sulfuric acid in the amount of lrom 300 to 400 pounds of acid per barrel oi oil and at a temperature in the range of atmospheric to F. to form a sludge layer and a suiionated oil layer, removing the sludge layer, adding from 3% to 5% or water to the sulionated oil layer and settling to obtain an oil layer and a sulfonlc acid layer, withdrawing the sulionlc acid layer and contacting it with a solution or an alkali metal hydroxide to form a soap, adding isopropyl alcohol to the soap to form an admixture, extracting the admixture with a light hydrocarbon, distilling the extracted mixture to remove alcohol and light hydrocarbons therefrom, and subsequently settling to form a layer of waterinsoluble soap and a layer of water-soluble soap and removing the water-soluble soap as product.

3. A method for producing a detergent suitable for use as a shampoo comprising the steps of extracting a naphthenic distillate fraction having a viscosity in the range of '15 to 85 seconds Saybolt at 100 F. with a selective solvent maintained under conditions to form an extract having approximately 35% of the volume of the original distillate and a raflinate, separating the extract from the rafilnate and admixing therewith 98%-sul- (uric acid in amounts ranging from 300 to 400 pounds of acid per barrel oi. extract and at a temperature inthe range of atmospheric to 170 F. to form a sulfonated oil portion comprising approximately 50% oi. the extract and a sludge portion, settling to form a sludge layer and a sultonated oil layer, removing the sulfonated oil layer, adding from 3% to 5% water thereto and settling to iorm an oil layer and a sulionic acid 6 layer, withdrawing the sulfonic acid layer and contacting it with a solution of alkali metal hydroxide in an amount sufficient to neutralize the sulfonic acid layer and form a soap. mixing the resulting soap with an equal volume of isopropyl alcohol, adding to the mixture of soap and isopropyl alcohol a light hydrocarbon in the amounts of 2 volumes of soap alcohol mixture to 1 volume oi a light hydrocarbon and subsequently settling to obtain a light hydrocarbon layer, an alcohol aqueous and soap solution layer, removing the alcohol and aqueous soap solution layer and distilling to remove alcohol therefrom, removingalcohol-free suli'onic soap solution from the distillation step and settling to form a layer 01 water-insoluble soap and a. layer of water-soluble soap and removing the layer of water-soluble soap as product.

JERE C. SHOWALTER. 

